The present invention relates generally to an exhaust gas manifold assembly for an internal combustion engine and more particularly to an assembly which includes a plurality of branch pipes each connected to introduce exhaust gas into the manifold of the assembly. Each of the branch pipes is connected between an exhaust port of a cylinder of an internal combustion engine and the exhaust system manifold in order to direct exhaust gas from the cylinder ports into the manifold. The manifold includes a main exhaust pipe through which gases are exhausted from the manifold. The catalytic converter which is utilized is of the type comprising a cylindrical configuration having an annular cross section.
In manifold assemblies of the type to which the present invention relates, exhaust gas released from the exhaust ports of respective cylinders of the engine pass through the respective branch pipes to a junction with a main exhaust pipe from which the exhaust gas is further passed through a hollow cylindrical catalytic converter disposed within the exhaust system. The gases flow radially through the converter into its hollow inner core and then flow axially thereof through the main exhaust port.
In such pipes of exhaust systems, it is highly desirable to increase the exhaust gas cleansing efficiency of the catalyst and to improve durability of the converter receptacle. Furthermore, it is beneficial if the exhaust gas distribution within the catalytic converter be maintained as uniform as possible.
The present invention is aimed toward improving the performance of such exhaust manifold assembly systems having the catalytic converter incorporated therein. The effects of the present invention are produced by appropriately arranging each of the branch pipes entering the manifold in a particular orientation taken relative to the structure and configuration of the catalytic converter contained within the manifold.